Train dispatching system for railroads



J1me 1937. F. B. HITCH COCK ET AL 2,082,162

" TR AIN DISPATCHING SYSTEM FOR RAILROADS Filed March 9, 1929 5Sheets-Sheet l imagawww 6M2,

S'Shets-Sheet 3 F. B. HITCHCOCK ET AL TRAIN DISPATCHING SYSTEM FORRAILROADS Filed March 9, 1929 June 1, 1937.

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uON QON Q WW W June 1, 1937- F. B. HITCHCOCK ET AL 2,082,162

TRAIN DISPATCHING SYSTEM FOR RAILRQADS Filed Mafch 9, 1929 5Sheets-Sheet4 mmwazzww, Y Y

ATTORNEY June 1, 1937. 7 F. B. HITCHCOCK ET AL 2,982,162

I TRAIN DISPATCHING SYSTEM FOR RAILROADS Filed March 9, 1929 5Sheets-Sheet 5 263 FIG. 3.

patented June 1, 1937 UNITED STAES PATENT OFFICE TRAIN DISPATCHINGSYSTEM FOR- RAIL- ROADS Application March 9, 1929, Serial No. 345,667

24 Claims.

This invention relates to a train dispatching system of the type, inwhich the dispatcher can control distant switch machines, and in whichtrains are dispatched by wayside signal indications, and in which theindications controlling the signals and switch machines, and indicationsof the progress of I trains, are transmitted over a comparatively fewline wires, by apparatus of the synchronous selector type.

In order that a dispatcher may properly dispatch the movement of trains,he should have control over the switch machines and signals, such thatthey may be moved in rapid succession, which results in the necessitythat he should from time to time be informed as to the progress of saidtrains along the track. This indication of train progress is known insignal parlance as OSing train movements. It is understood by thoseskilled in railway practice, that OS indications may come insimultaneously and in close ly spaced or overlapped relations, and forthis reason a synchronous selector type system, for transmitting such OSinformation, lends itself to this function admirably, this being becausea a synchronous selector type system permits the transmission of a verylarge number of distinctive indications over the same line wire within avery short period of time.

However, there are limitations to the extent to which a synchronousselector of the rotary arm type may be used. This is because there is alimit to the size to which a rotary selector may be built, thus limitingthe number of what we shall term message channels, also the necessityfor speed, limits the size or compactness, as well as the ruggednessthat may be built into such a selector. Also, such selectors must bebuilt for a given number of message channels, which means that a needfor additional channels, would require all existing selectors to bereplaced by new ones.

In view of the above considerations and others, it is proposed to usefor dispatching purposes in accordance with the present invention, aselfstepping synchronous selector system, in which the rotary armselector, such as set forth in the patent to R. C. Leake, Patent No.1,794,628 dated March 3, 1931, is replaced by a sufiicient number ofrelays, both in the dispatchers oflice and in each way-station, to setup the required number of message channels. In accordance with thepresent invention, it is proposed to transmit a plurality of alternatepositive and negative impulses over the stepping circuit, including thestepping wire and the common return wire, of

which, each impulse will energize and move one of the above mentionedrelays in the dlspatchers ofiice and one in each way-station, and duringthat period of time which exists between the movement of two successiverelays, either a conway-stationyand also, the system as proposed,

stops automatically at the end of the period of time that is required totransmit all of the indications, which period of time may be no shorterthan two complete cycles. Other features of the present invention residein the construction and 1 arrangement of parts to establish synchronismbetween the banks of message channel selecting relays at various waystations and with the dispatchers bank of message channel selectingrelays, as well as the added feature of a novel circuit, so arranged, asto permit the use of a comparatively small number of relays to give thenumber of message channels desired. I

Other objects, purposes and characteristic features of the presentinvention will in part be obvious from the accompanying drawings, and inpart pointed out as the description of the invention progresses.

In describing the invention in detail reference will'be made to theaccompanying drawings, in which:-

Fig. 1A and Fig. 1B placed end to end, illustrate conventionally theequipment in the dispatchers oflice of a simplified system, illustratingthe apparatus for controlling the switch machines and signals at one endof a passing siding;

Fig. 10 illustrates the equipment of one way station with the apparatusconventionally shown connected to the control relays for the switchmachine and signals at one end of a passing siding; Fig. 2C illustratesthe equipment of a way station showing a modification of the connectionsthat may be used, so that a large number of message channels may be setup with comparatively few relays;

Fig. 3 illustrates in a symbolic manner the various combinations ofcontact positions and the message channels obtained thereby for messagechannel selecting relay bank shown in Fig. 2C; and

Fig. 3A illustrates diagrammatically the symbolic showing of thecombination 8 of Fig. 3.

Description of apparatus Although in practice the dispatcher controlsthe switch machines and wayside signals of a large portion of a railwaysystem, possibly including many passing sidings, diverging routes, drawbridges, railway crossings, and the like, the present invention has forconvenience been shown as applied to the apparatus located at the westend of the passing siding PS (see Fig. 10) connecting to the main trackTK of a single track railway system, signalled withabsolute-permissive-block signalling to the track section, preceding thetrack section (as shown in Fig. 1C) enclosed by the insulated jointsI82. The west end of this passing siding contains the track switch TSWThis switch has associated therewith the usual detector track circuitinsulated from the rest of the track by insulating joints I82, andincluded therewith the fouling section PS of the passing siding PSconnected by wires I89 and H98 in the usual manner. This detector trackcircuit contains the usual track battery I9 I and track relay TR Thestarting signals for the main track and siding at the west end of thepassing siding PS have been designated SW and SW respectively, and thecorresponding entering signals have been designated SE and SE In thetower is preferably located a miniature track layout corresponding inevery detail to the system over which the dispatcher has control, and inthe particular arrangement shown includes only the passing siding PS.This miniature track layout has an indicating lamp I associatedtherewith, which if illuminated indicates the occupancy of thecorresponding detector track circuit, namely, the detector track circuitcontaining the track relay TR The track switch TSW at the west end ofthe passing siding PS is preferably controlled by a switch machine SMwhich switch machine is preferably controlled by the switch machinerelay SMR which relay is in turn controlled by the lever SML through themedium of the self stepping synchronous selector system hereinafterdescribed. Similarly, the signals SE SE SW and SW are controlled by thesignal relay SR and the direction relay DB through the medium of thesynchronous selector system in accordance with the position of the leverSL located in the dispatchers ofiice.

With the drawings, Fig. 1A and Fig. 1B placed end to end, we have anillustration of the dispatchers office, having a bank of message channelselecting relays l to I l inclusive, which are controlled through a linerelay LP, by alternate positive and negative impulses set up by a masterrelay MR, and two time spacing repeater relays S and S The master relayMR and its spacer relays S and S are interconnected to produce anon-mechanical rotation, which results in a positive or a negativeimpulse being placed on a stepping wire Zfil when the relay MB is in itscorresponding energized position. The operation, of this impulsegenerating group of relays, is controlled directly by a controlrepeating relay CRR which is in turn controlled by a control relay CRand an initiation relay IN, which is initiated either by a movement of acontrol lever such as SL or SML, or by'connecting a message wire 202with a common wire 299 while the system is at rest.

The dispatchers ofilce equipment is connected to a way station equipmentor equipments such as illustrated in Fig. 1G by three line wiresconsisting of a common wire 209, a stepping wire 20!, and a message wire262. The way station as illustrated in Fig. IC has a line relay Lconnected in series in the stepping wire 26! and with the line relay Lin the dispatchers oilice. The line relay L controls its bank of channelselecting relays I to i inclusive. It is obvious that the operation ofthe channel selecting relays to l in the way station will be insynchronism with the channel selecting relays i to H in the dispatchersofiice, due to the fact that the line relays L and L are connected inseries and by reason of the similarity of their circuit connections.With the system initiated and the relays I to H inclusive being operatedsequentially and in synchrcnism with the relays i to l inclusive, acontrol, or other indications may be sent, or received, over apredetermined message channel, which occurs at a predetermined time inthe operation cycle of the sequentially operated message channelselecting relays.

For convenience. in explanation of the circuits and relays involvedtherein, the relays of the same type have been given characteristicletters having the individual relays distinguished by suitableexponents, with each type of relay having the characteristic features asbriefly summarized below, with any variations to meet a specific case,mentioned where that specific example is set forth.

(1) The relays i to 67 inclusive, Figs. 1A and IB, the relays, l to linclusive, Fig. 1C, and the relays A, B, C and D, and X, Y, and Z, Fig.20, used to produce the non-mechanical rotation by successive relaymovements, are of the polar permanent magnet stick type. In other words,when an energy impulse of a certain polarity has been applied, and hasmoved its contacts to the position determined by the polarity, apermanent magnet incorporated within the relay holds the armature inthat position. The OS relay and the relays S and S are also of the polarstick type.

(2) The line relays L and L are polar, biased to neutral, type relays,which respond in such a manner that their contacts are held in neutralor non-contact-1naking positions during the time that no energy isapplied, but are moved either to the right or to the left as positive ornegative impulses, respectively, are applied.

(3) The relays ST", ST etc. are neutral relays, having thecharacteristic feature that they do not pick up upon application ofimpulses, which are of the normal rate, sent over the stepping circuit;but upon application of a long impulse their armatures are picked upwithin a predetermined period of time, which period of time is apredetermined fractional part of the total duration of the long impulse.

(4) The relays IN, IN etc. are neutral relays, which may be either quickor slow acting during their release period, as the necessity of aspecific case demands.

(5) The relay OR is a neutral relay with two windings, so designed thatthe armature will pick up with a certain normal value of current flowingin either winding.

It will be stated here, that each polar relay is considered to assume aright hand or positive position, with an application of positivepotential to the left hand terminal of the relay, and to assume a lefthand or negative position, with an application of negative potential tothe left hand til terminal of the relay. It is also assumed that thenormal positions of all relays are their present full line positions, sothat when a relay is spoken of as being in a reverse or abnormalposition, it shall mean the dotted position as shown in the accompanyingdrawings.

The levers I8, I9, and 20 are connected together mechanically, as arealso the levers 2I and 22, so that the movement of the controllinghandles SL or SML, respectively, will move the inter-connected leverstogether. It will be observed, that the levers I8 and 2i make contactwith the common wire at points I86 but momentarily, as the levers aremoved to their dotted line positions.

It is believed that the features of the system will be better understoodby considering its operation.

Operation The apparatus and circuit arrangement embodying the presentinvention may be divided into two distinct groups, as follows: (1) Thestepping, or synchronizing circuit arrangements and mechanisms whichhave a major function in producing a non-mechanical rotation bysuccessive relay movements occurring in exact synchronism, and whichprovides that the system shall be normally at rest, but shall beinitiated for synchronous rotation of relay movements, either, when thedispatcher operates a lever to control a distant function, or when an OSindication is present at a waystation ready for transmission to thedispatchers office, and to be stopped at the end of the second cycle ifthere are no further indications to be transmitted; (2) a messagechannel circuit arrangement and mechanisms, which have a major functionof utilizing the non-mechanical rotation of successive relay movementsin producing temporary message channel circuits, which are completedduring the period of time intervening between the final movement of onerelay and the initial movement of the next relay in succession, whichmessage channel circuits are to be used for transmitting impulses eitherfor OS indications or for controlling switch machines, way side signals,de-rails and the like.

Operation of the synchronizing circuits As has been explained, the linerelays L and L are energized by the impulses which are impressed on thestepping wire 25. These line relays serve to repeat for the localcircuits, the impulses passed over the stepping wire, so that themessage channel selecting relay banks may be synchronously operated.

These message channel selecting relays are of the polar stick type,which have the required number of contacts to meet the needs in aspecific location in the circuits. The first two of these contacts arebreak and make beyond center, for use in the operating circuits of therelays. In other words, the circuit for operating each relay, is carriedthrough one of two of its own contacts, so that one contact must breakand make beyond center, when the contacts are moved in one direction,and the other contact make and break beyond center when the contacts aremoved in the other direction. This is to insure that no relay shallbecome stuck on center.

The message channel selecting bank of relays is so organized, that themovement of one relay to a given position, opens its own circuit andcloses the circuit for the next relay to be operated. This means thatthe polarity of successive relays must be alternated, so that animpulse,

which operates a given relay, willnot operate the next relay insuccession, when its circuit is closed, but rather must require animpulse of the opposite polarity. With this organization of apparatusevery impulse produces a definite predetermined result, which as appliedto the banks of relays as shown in Figs. 1A, 1B and 10, determines thatthe number of relays in the banks shall be an odd number, so that everyimpulse shall be an active one.

The relays I to I! inclusive, and the relays I to I inclusive, operatein identical fashion, such that impulses alternately negative andpositive, placed on the wire 22%, connected to the contact 32 of relay I(see Figs. 1A and 1B) and the wire 228 connected to the contact I 88 ofrelay I (see Fig. 1C) energize the successive relays in succession toreverse positions. Also, impulses, alternately positive and negative,placed on the wire 226 connected to contact 33 of relay I, and on thewire 229 connected to the contact I09 of relay I energize the successiverelays in succession to their normal positions. Thus, the circuitarrangement is so organized that relay I moves its contacts to anegative position with a negative impulse, relay 2 moves its contacts toa positive position with a positive impulse, and relay 3 moves itscontacts to a negative position with a negative impulse, and in likemanner all relays operate to a reverse position.

More specifically it will be stated, that alternate negative andpositive impulses applied to the stepping wire 20I, are repeated by therelay L in such a manner that alternate negative and positive impulsesare placed upon wire 228 receiving energy from battery I81 and I88through contact I04. These impulses are routed, so to speak, through thewire 228 to the contact tilt of relay I I. This contact directs theimpulses on either wire 224 or wire 226, according to its position.

Let us assume, that a negative impulse is placed on the wire 224. Thisimpulse passes through positive contact 32, through relay I, to common,thus moving its contacts to a negative position. Should that negativeimpulse on the wire 22d continue after the relay I has moved itscontacts to the negative position, that impulse would be applied torelay 2, through its negative contact 35, but since relay 2 is alreadyin the negative position, the negative impulse will not efiect itsmovement. However, the positive impulse which is next placed on wire 224flows through negative contact 32 and negative contact 35, through relay2, which moves its contacts to a positive position. Should that positiveimpulse continue after the relay 2 has moved its contacts to a positiveposition, that impulse would be applied to relay 3 through positivecontact 39, but as relay 3 is in a positive position it does not affectmovement thereof. The negative impulse next placed on wire 22 i flowsthrough this circuit in suchv a manner as to move the contacts of relay3 to a negative position, and in like manner as positive and negativeimpulses are placed on the wire 224, the relays in the bank aresuccessively moved from their normal full line position, to theirreverse dotted line positions, until the last relay and return relay Ito its normal position. The movement of relay I to a positive position,sets up the circuit for relay 2 through positive contact 36. But relay 2is at this time in a positive position and does not respond to thatpositive impulse even if it should be indefinitely prolonged. However,the next successive impulse, which is negative, moves the contacts ofrelay 2 to a negative position, thus setting up the circuit for relay 3.In like manner, the relays I to I 6 inclusive are returned to theirnormal positions.

The relays I to II, as shown in the drawings, Figs. 1A and 1B, areassumed to have been reversed and relays I to It to have been returnedto their normal positions thus leaving the circuits as shown in thedrawings. With such a condition obtaining, a circuit is made up for thepositive and negative impulses repeated at contact IM, asfollows:through wire 228 negative contact I09, wire 226, positivecontact 33, negative contact 36, positive contact 40, negative contact44, positive contact 48, negative contact 52, positive contact 56,negative contact 80, positive contact 64, negative contact 68, positivecontact I2, negative contact I6, positive contact 88, negative contact84, positive contact 89, negative contact 94, negative contact 99, wire221, through relay ST" to common. As has been explained heretofore therelay ST does not pick up upon the impulses of the normal stepping rate,so that the relays must stop at the end of each cycle, because norelease can be obtained at the end of the cycle of a relay bank untilthe corresponding relay ST or ST has been picked up.

It will be noted here, that it is desirable that the system shall gothrough at least two cycles after it has been initiated, and then ceaseoperation providing that all OS indications have been received. In orderto accomplish this, the circuits of relays IN and CR are so arranged,that when the relay IN is energized the relay OR is energized. Thismeans that, as the system is approaching the end of a cycle, the stickcircuit of the relay CR must be opened preceding the opening of thestick circuit of the relay IN, so that the relay CR will not drop, aswill the relay IN at completion of the first cycle, but will drop at theend of the second cycle, To do this, the contact 9'! has connected inparallel with it the contact I94, in such a manner, that the resultingcombination, of the two contacts is such,

that the stick circuit of the relay IN is completed through eithercontact 91 or contact I94, except during the period of time that existsafter the initiation of contact 9'! toward its normal position, and thetime that the contact I96 again assumes a reverse position. This may beexplained by saying that, with the relays l6 and IT with their contactsin the present normal positions, contact will be made, when contact I94is moved to a positive position, so that wire 2I8 is then connected tocommon wire 280, through Wire HI and positive contact 596, but whennormal contact 97 is reversed, the wire 2I8, is connected to the commonwire 2%, through positive contact 91. Then, with the next relaymovement, which is the movement of the contacts of relay IT to anegative position, the circuit from wire 2I8, through positive contact91, to the common wire 200 is still made, although broken at contactI94. However, on the next half cycle when the relays return to theirnormal position, the circuit through positive contact 97, is broken, andis not again made until the contact I94 returns to a positive position.Thus, it is seen that the circuit under consideration is broken only atone time, which time is at the end of each cycle completed by themessage channel selecting bank of relays I to H inclusive.

In the same manner, the stick circuit for the relay CR has the contact8'! connected in parallel with contact 92, which thus accomplishes thesame result, as the contacts 91 and I9 1 connected in parallelaccomplish for the stick circuit of relay IN. The stick circuit of therelay CR is momentarily open during a period of time preceding thatperiod during which the stick circuit of relay IN is open. It will nowbe seen that upon nearing the completion of the first cycle of thenon-mechanical rotation, as the relay I4 has returned its contacts tothe normal position, the stick circuit for the relay CR is broken, butthe relay CR does not drop due to the fact that the current for therelay IN flows through its upper winding. Upon movement of the contactsof relay I5 to their normal position, the stick circuit for the relay CEis again closed, and the stick circuit for the relay IN is opened uponmovement of the contacts of relay I6 to their normal position, whichimmediately drops the relay IN. The relay IN remains de-energized due tothe dropping of its front stick contact 23. As the rotation of themessage channel selecting bank of relays nears the completion or" itssecond cycle, the stick circuit for the relay GR is again opened, andthe relay CR drops due to the fact that the relay IN has formerly beende-energized.

The control relay CR, as its name implies, controls the initiation andstopping of the impulse generating group composed of relays MR, S and SBut in order that the starting condition may be fulfilled, namely, along positive impulse to pick up the relay ST and ST etc., a controlrepeating relay CRR. is interposed in the control, to produce the longpositive impulse upon the stepping wire 20L During the period of timewhich exists after the relay CR has been energized, and before the relayCRR picks up, there is a circuit completed which places positivepotential upon the relay MR. Thus, a positive impulse is placed upon thestepping wire 2IlI. This positive impulse is maintained until the relayST has picked up and the relay I! has moved its contacts to a positiveposition, thus closing a circuit for picking up the relay CRR. Thepicking up of relay CRR reroutes the stick circuit of the relay INthrough the front contact I95 to the wire 258, which is connected, atthis time, to the common wire 290. Also, the relay CRR must be slightlyslow releasing, sufiiciently to prevent the back contact I95 to make,before the front contacts 23 and I9! of the relay IN break. Failure todo this would cause the system to continue operation after the end ofthe second cycle.

The picking up of the relay CRR cuts off the positive potential appliedto the relay MR, through back contact I 65, and closes front contactI06. The closing of contact I86, gives a potential to the relay MR asdetermined by the position of relay S The long positive potential onrelay MR moved its contacts to a positive position, which energized thecontacts of relay S to a positive position, which, with said contacts ofrelay S in such a position, energizes the contacts of relay S to anegative position, thus placing negative potential on the relay MR whenfront contact I06 of relay CRR is closed. With negative potential onrelay MR, its contacts assume a negative position, which energizes therelay S to move its contacts to a negative position, which in turnenergizes the relay S to move its contacts to a positive position,placing positive potential on the relay MR. Thus we have shown how thesuccessive operation of the relays MR, S and S occur, to producealternate positive and negative impulses used for stepping.

It will be noted here that the time interval of these impu se-s isdetermined by the operating time of the relays included within theimpulse generating group. Also, it is seen that this group can not getahead of the line relays, as the relay S is in series with said linerelays.

We will now assume that all the apparatus in the dispatchers office andin the way station (as illustrated in Figs. 1A, 1B and 1C, placed end toend) to be at rest. To illustrate the starting of the apparatus, therevolving of the message channel selecting relays in a non-mechanicalrotation, to illustrate how the alternate positive and negative impulsesare produced by the impulse generating group, operating in anon-mechanical rotation, and to show the results of the movement of acontrol lever, we will assume that the dispatcher desires to move theswitch TSW from the normal position to a reverse position routing theeast bound main-line traffic onto the passing siding PS The movement ofthe track switch TSW is controlled by the switch machine SM associatedtherewith, which is in turn controlled by the switch machine relay SMRWith the polar contact of the relay SMR in a right hand or positiveposition, the switch machine operates so that the switch TSW assumes anormal position allowing east bound traflic to proceed upon the maintrack, and with the polar contact of relay SMR in a negative orleft handposition the switch machine SM operates to move the track switch TSW toa reverse position allowing the east bound traffic to proceed onto thepassing siding PS The position of the polar contacts or" the relay SMRis determined by the position lever SML by means of a control impulsetransmitted to the relay SMR through the medium of the synchronousselector system hereinafter described.

We will now assume that the dispatcher moves the lever .SML to negativeposition. During the movement of this lever to a negative position, thelever 2i makes momentary contact IBiS which sets up a circuit asiollows:--from positive battery 5-33, through wires 233, ZI'I', 2I6, and'2 I5, through the upper winding of relay CR wire 2H5, relay IN, wireEli-s, lever 3, contact iilli, to the common wire This momentary circuitenergizes the relays IN and CR, in as much as the current that flows inthis circuit passes through the upper winding of the relay CR and thewinding of relay IN connected in series. These relays CR and Ill areheld ene zed through stick circuits completed by their front contacts 25and 23 respectively. The stick circuit for the relay IN may be traced Uilows:-positive battery from battery througn wires 203, 2H, 2M5, 2E5,relay CR, wire relay IN, wire 223, front contact 23, 2923, back contact995, to the common wire The stick circuit for the relay CR may be tracedas fo1lows:positive battery from the battery 82, wire 2%, Ell, H3, and2H), lower winding relay CR, front contact i l, wire 2W, positivecontact 92, to the common wire 2%.

The energization' of the relay CR causes positive potential to beapplied to the relay MR through a circuit traced, as follo-wsz-positivebattery from the battery I83, wires 283, Ml, 2I6, 224, 225, negativecontact Hi2, wire 7226, back contact I05, wire 221, front contact 26,wire 218, through the relay MR to the common wire 200. This positivepotential applied to relay MR moves contacts 21 and 28 to a positiveposition. With contact 21 in a positive position a circuit is set up asfollows:positive battery from battery I83, through wires 2M, positivecontact Zl, wire 279, relay S wire ZIlI, relay L wire 2M, relay L to thecommon wire 2%. With this circuit closed, current flows through thewindings of relays L and L to move their contacts to a positiveposition.

With the contact I34 of relay L in a positive position, positivepotential is placed on the relay ST through a circuit traced asfollowsz-positive battery from battery I31, through wire 228, negativecontact IDI) of relay Ill, wire 225, positive contact 33 of relay I,negative contact 36 of relay 2, positive contact M] of relay negativecontact 44, positive contact 48, negative contact 52, positive contact56, negative contact til, positive contact 64, negative contact 68,positive contact I2, negative contact I3, positive contact 89], negativecontact 84, positive contact 89, negative contact 94, negative contact99, wire 22l, through the relay ST to common; During the time that thecontact I04 of relay L is in a positive position this circuit ismaintained so that the relay S'I will pick up in a predetermined lengthof time, which is slightly greater than the pick up time of relay ST Atthe same time that the relay ST is picking up due to the positivepotential being placed upon it, the relay ST is being picked up througha circuit traced as followsz-positive battery from battery I98, positivecontact Hill, wire 230, negative contact I34, wire 229, positive contactI09 of relay I negative contact I I3 of relay 2 positive contact II'I ofrelay '3 negative contact I2I of relay 4 positive contact I25 of relay 5negative contact I29 of relay 6 negative contact I33 of relay I throughthe relay ST to common. As the relay ST requires less time to pick upthan the relay ST", said relay ST will close its front contact I36,allowing positive potential flowing from the battery I38 through thecircuit just traced for relay ST to be also placed upon the relay Ithrough front contact I 35, wire 23L through relay I to common, thusenergizing the relay I so that its contacts move to a positive position.Similarly, the relays of the type ST in all other way stations of such asystem will pick up and allow the last relay of the message channelselecting group over which they control, to be energized to a'positiveposition.

As soon as the relay ST picks up its front contact I03, a circuit iscompleted so that positive potential from the battery I81 flows throughthe circuit heretofore traced for the relay ST, being shunted from therelay ST through the front contact I03, wire 280, through relay I I tocommon. Thus the contacts of relay 51 are moved to a positive position.

The movement of the contacts of relay I! to a positive position, opensthe circuit (heretofore traced) at the contact I32 of relay 1?, forplacing the positive potential on the relay MR. Also, as soon as thecontacts of relay Il assume positive position a circuit is completedwhich energizes the relay CRR through the circuit traced as 01-lows:positive battery from battery I83, through Wire 203, 2H, 222, frontcontact 25, wire 223, to relay CRR, wire 2| 8, and 22I positive contactI 94 of relay IT, to the common wire 200.

With the relay CRR energized, its front contact I05 closes a circuit,which permits a potential of a polarity as determined by the position ofcontact 29 of relay S to be placed upon the relay MR. The relay MRhaving been previously energized with a positive potential, causes thecontacts of relay S to assume a positive position through a circuitheretofore traced. With the contact 30 of relay S in a positive positiona negative potential is placed upon the relay S through a circuit tracedas follows:--from the negative battery I 84, through wires 208, 209 and2I0, positive contact 30, wire 2, through the relay S to the common wire200. Thus the contact 29 of relay S is energized to a negative position.When the relay CRR is energized, and its front contact I06 is closed,the potential placed upon the relay MR is negative and flows through acircuit traced as follows:from negative battery I84, wires 208 and 209,negative contact 29, wire 206, front contact I06 of relay CRR, wire 218,through the relay MR to the common wire 20!]. This negative potentialplaced upon the relay MR causes its contacts to be moved to a negativeposition, causing the result that a negative potential is placed uponthe relays S L and L in series through a circuit traced as follows:fromnegative battery I84, through wire 2I2, negative contact 21, wire 219,relay S wire 20I, relay L, wire 20I, relay L to the common wire 200.

The energization of relay CRR, also re-routes the stick circuit of therelay IN through a circuit traced as follows:positive battery from thebattery I83, through wires 203, 2I'I, 2H5 and 2I5, relay CR, wire 2I4,relay IN, wire 228, front contact 23, wire I96, front contact I95, wirev2IiI, front contact I91, wire 260, and H8 and 22 I, positive contactI94 of relay IT to the common wire 200.

With a negative potential on the relay MR due to the energization of therelay CRR, a negative potential is placed upon the relays S L and Lwhich moves their contacts to a negative position. With the contact I04of relay L in a negative position a circuit is set up which placesnegative potential on the relay I, being traced as follows:from thenegative battery I88, through negative contact I04, wire 228, positivecontact I88 of relay I'I, wire 224, positive contact 32 of relay I,through the relay I to common, thus energizing the relay I to move itscontacts to a negative position. At the same time the contact I07 ofrelay L is in a negative position, which places negative potential uponthe relay I through a circuit traced as follows:- from negative batteryI99, through negative contact I01, wire 230, positive contact I34, wire228, positive contact I08, through the relay I to the common wire 200.The relay I is thus energized to move its contacts to a negativeposition. Also, at the same time, the contact 35, of relay S is in anegative position which completes a circuit to place positive potentialon the relay S with the circuit being traced as follows: from thepositive battery I83, through wires 203 and 284, negative contact 30,wire 2| I, through relay S to the common wire 200. Thus the contact 29of relay S is caused to move to a positive position which results in apositive potential being placed upon the relay MR through a circuittraced as follows:from the positive battery I83, through wires 233, 204,and 205, positive contact 29, wire 286, front contact I05 of relay CRR.wire 218, through the relay MR to common. Thus, the contact 21 of relayMR is moved to a positive position, placing a positive potenial upon therelays S L and L through a circuit as heretofore traced.

It will be here pointed out that as the relays S L and L are in seriesthey will operate at the same time, provided that they are built withthe same operating characteristics. This being so, the relay S willoperate its contacts at the same time that any message channel selectingrelay operates its contacts, thus causing the result that as soon as amessage channel selecting relay has been energized in the dispatchersoffice and corresponding message channel selecting relay has beenenergized at each way station simultaneously with the energization ofthe relay S then the relay MR is energized to an opposite position. Thusin like manner the impulse generating group of relays composed of relaysMR, S and S proceed to operate in a non-mechanical rotation until theircircuit is again opened at the contact I06 of relay CRR.

The next impulse which is produced by the relay MR, is repeated by theline relays L and L As the last impulse was negative and moved thecontacts of relays I and I to a negative position, then the next impulseis positive and is repeated by the relay L in the dispatchers ofiice,which establishes a circuit traced as follows:-- positive battery I87,through positive contact I94, wire 228, positive contact I00, wire 224,negative contact 32, negative contact 35, through the relay 2, to thecommon wire. Thus the contacts of relay 2 are energized to the positiveposition. Likewise the positive impulse repeated by the relay L in theway station shown in Fig. 1C flows through a circuit traced as follows:-from positive battery I98, through positive contact I97, wire 235,positive contact I34, wire 228, negative contact I08, negative contactII 2, through the relay 2 to the common wire. Thus the contacts of relay2 are moved to a positive position.

With the relays 2 and 2 in positive positions a circuit is set up duringa central portion of the total channel time, as explained hereinafterwhich allows negative potential to be placed on the relay SMR beingtraced as follows:- from the negative battery I84 through wires 200,233, lever 22 in a left hand position, wire 235, positive contact 37, ofrelay 2, positive contact M of relay 3, negative contact 45 of relay 4,positive contact 49, negative contact 53, positive contact 51, negativecontact 6|, positive contact 65, negative contact 69, positive contactI3, negative contact 'I'I, positive contact 8|, negative contact 85,positive contact 90, negative contact 95, positive contact IEII, throughwire 232, positive contact 3 I, wire 236, negative contact 28, Wire2532, to the Way station, wire 24L positive contact I35, negativecontact I30, positive contact I25, negative contact I22, positivecontact H8, positive contact II 4, through the relay SMR to the commonwire 200. Thus the polar contact of relay SMR is moved to a negativeposition effecting a control of switch machine, which in turn moves theswitch TSW to a reverse position routing the east bound traffic onto thepassing siding PS.

The succeeding negative and positive impulses sequentially operate therelays 3, 4, 5, 6, I, 8, 9,

I II, II, I2, I3, and I4 to their respective reverse positions, in asimilar manner as explained for relays I and 2. When the contacts ofrelay I i assume a reverse position, the contact 81 completes a circuitin parallel with contact 92, so that the next impulse which is negativeand moves the contacts of relay I5 to a reverse position, does not openthe stick circuit of relay CR. Likewise the next positive impulse whichenergizes the contacts of relay I6 to a reverse position, moves contact91 to a reverse position which completes a circuit in parallel withcontact I 94, so that although the circuit through the contact IS ofrelay I7 is broken upon the application of the next negative impulse,the stick circuit for the relay IN, and the energizing circuit for therelay CRR is still maintained. Now that the relays I to II inclusive,have gone through onehalf their cycle, the contacts of relay II are thenin a negative position, which routes the stepping impulses through thewire 226 instead of wire 224, so that the relays I to I Ii may bereturned to their normal positions, and it is assumed that they are soreturned. During this second half cycle, these relays are returned totheir normal position sequentially, and when the relay I l returns toits normal position the stick circuit for the relay CR was opened andagain closed upon movement of relay I5 to a normal position, but did notdrop relay CR, due to the fact, that the current for relay IN wasflowing through the upper winding of relay CR. With the relays I to I itin their normal positions, the circuit for picking up the relay ST iscompleted, and also the circuit including the relays CRR and IN inmultiple is opened, thus dropping both the re lays CRR and IN. Thedropping of relay CRR closes the circuit for placing a positivepotential upon relay MR through the front contact 26 of relay CR andback contact I 85 of relay CRR.

Thus in due time, the relay ST again picks up and the relay I I isenergized to the positive position, which again picks up the relay CRR,causing the generation of positive and negative impulses by the impulsegenerating relay group S S MR, which impulses are applied to thestepping wire 2III. The channel selecting relays complete another cycleduring which time the relay CR, is deenergized by the movement ofcontact 8'! of relay I l to a normal position,

which is possible inasmuch as the relay IN is now deenergized. Thedropping of relay CR also in turn drops the relay CRR, which has a slowreleasing period to an extent that the impulse generating group willproduce at least two'impulses after the stick circuit of relay CR hasbeen opened. Thus two cycles of operation have been completed.

The operation of the control circuits for the relays I to I inclusiveand the relay ST is identical to that explained for the relays I to I"!inclusive and the relay ST".

Let us now consider the synchronous operation of the message channelselecting bank of relays in the dispatchers office, in regard to theirco-op-eration with a message channel selecting bank of relays at a waystation such as shown in Fig. 10. As the long positive starting impulsepicked up the relays ST and ST and the relays El and "i are energized toa positive position, the first negative impulse energizes relays I and Ito a negative position. Likewise the next succeeding positve impulseenergized relays 2 and 2 to a positive position, with each succeedingimpulse energizing its respective corresponding relay, until relays 1and '1 have been energized to a negative position. The next succeedingimpulse is a positive impulse which energizes relay 8 to a positiveposition and relay I to a positive position. Likewise the succeedingnegative impulse energizes relay 9 to a negative position, and relay 2to a negative-position, until relay I3 has been energized to a negativeposition and the relay 6 has been energized to a negative position. Thefollowing impulses which are used in the dispatchers oflice to completethe cycle in the relays I to I! inclusive are absorbed at the waystation in the relay ST without producing any relay operation. So it iseasily seen that should the way station relays for any reasonwhatsoever, such as extraneous foreign impulses, or lack of immediateresponse of a relay, be out of step, that these extra impulses generatedat the dispatchers omce, would bring the way station up to the end ofthe cycle. Thus, at the end of each cycle, the relays at the dispatchersofiice and the relays at the way station are again synchronized.

It will be stated here that should the lever SL be moved to either ofits extreme positions, the system would be initiated and impulses of apolarity corresponding to the positions of the levers I9 and 20 would besent over their corresponding message channels, which are set up at asuitable time during the sequential operation of the message channelselecting relays, While they are completing one cycle. Let us as sumethat the lever SL is in the right hand position, moving the levercontact I9 and ZIP to a right hand position which clears the signal SEallowing traffic to proceed in an east bound direction. The messagechannel for lever contact I9, assuming that the message channelselecting relays have been stepped to their proper positions, may betraced as follows:-positive battery from battery I83, through wires 2%,EH, ZIS, 224 and 234, lever I9 in a right hand position, wire 238,negative contact 34, negative contact 31, positive contact 4|, negativecontact 45, positive contact 69, negative contact 53, positive contact5?, negative contact BI, positive contact 65, negative contact 69,positive contact I3, negative contact all, positive contact SI, negativecontact 85, positive contact 8G, negative contact $5, positive contactIIII, wire 232, negative c0ntact 3|, wire 23?, positive contact 28, wire202, to the way station shown in Fig. 16, wire 248, positive contactI35, negative contact Itil, positive contact I26, negative contact I22,positive contact IIB, negative contact II I, negative con tact Hi3,through the relay SR tothe common wire m. Thus the relay SR is energizedwith positive potential which causes its polar contact to assume apositive position as shown. The message channel for the lever contact26, assuming that the message channel selecting relays have been steppedto proper positions, may be traced as followsz-positive battery frombattery I83, through wires ZI'I, 2H5, 22-6 and 234, positive lever 26,wire 25B, negative contact II, negative contact 55, positive contact t9,negative contact 53, positive contact 57, negative contact {I I,positive contact negative contact 59, posi tive contact I3, negativecontact ll,positive contact 3|, negative contact 85, positive contactSII, negative contact positve contact IIPI, wire 232, negative contactSI, wire 231, positive contact 28, wire 202, to the way station shown inFig, 1C, wire 2M, positive contact I35, negative contact I30, positivecontact I26, negative contact 22, negative contact I !8, through therelay DB to the common wire 260. Thus the relay DB is energized withpositive potential causing its polar contact to be moved to a positiveposition.

Let us again assume that the system is at rest, and that a train entersthe track section TK The occupancy of track section TK shunts the trackrelay 'I'Pv so that its contacts I32 and 33 assume a de-energizedposition. As the contact is a make before break contact, a circuit ismomentarily completed from the battery 28!] through contact 538 and therelay IN to the common wire 2%. This momentary circuit energizes therelay IN which is a slow releasing relay, having a release periodsufficient to allow the system to complete one cycle before it isentirely de-energized. As the system is at rest, and the relay IN isenergized, a circuit is completed through the contact l3? of relay INwhich will initiate the system and is traced as follows:from thepositive terminal of battery i823, through Wires 293, 291, 2H5 and H5,upper winding of relay CR, wire 2M, relay IN, wire 239, negative contact92 of relay 15, negative contact 823 of relay ll, wire 202, to the waystation shown in Fig. 1C, wire 245, negative contact E35, negativecontact 13$, wire 2 59, front contact liil of relay IN, to the commonwire 230. Thus a current flows through the upper winding of relay CR andthe winding IN moving the contacts to an energized position, thusinitiating the system and stepping the message channel selecting relaysin sequential operation for completing two cycles for reasons heretoforeexplained. When the message channel selecting relays assume properpositions, which occurs once during each of the two cycles, a messagechannel is set up so that the OS indication, telling the dispatcher thatthe track section TK is occupied, may be transmitted. This messagechannel is traced as follows:negative battery from battery 288, throughback contact E33, wire 28. positive contact I22, positive contact l28,negative contact I311, positive contact 135, wire 2 5i, Wire 2922, tothe dispatchers office shown in Figs. 1A and IE, to the negative contact28, wire 236, positive contact 3!, wire 232, positive contact .itl,negative contact 95, positive contact 92, negative contact 85, positivecontact 8 l, negative contact ll, positive contact 13, negative contact69, positive contact 65, negative contact 69, positive contact 51,negative contact 53, positive contact 49, positive contact 45, wire 282,through the relay OS to the common wire 200. Thus the polar contact I ofthe relay OS is energized to a negative position illuminating theindicator lamp I, giving indication to the dispatcher that the tracksection TK is occupied.

It will be noted here, that the number of relays in the dispatchersoffice was arranged for use with the modified way station as shown inFig. 20. Thus, there is an excessive number of synchronizing impulseswhich are not practicable for the type of way station connections asshown in Fig. 1C.

When way stations, such as shown in Fig. 1C, are used in series,provisions must be made that each way station of this type must have anequal number of relays, which give the total required number of messagechannels. This is necessary, since, as soon as any one Way station comesto the at rest period, this station then has a message channel set upwhich is used for initiation. Should an OS indication occur at thisparticular station, then the message wire 202 would be connected to thecommon wire 20!] at this particular station, which condition wouldresult in the extermination of any control indications which might besent over the message wire for use at some other Way station, and forthis reason it should be understood that all way station relay banks ofa particular system should have the same number of channel selectingrelays.

Operation of message channel circuits After having explained thesynchronous operation of the channel selecting relays, we may nowconsider how contacts on corresponding relays in the two relay groupsclose synchronously to complete a plurality of sequentially closedmessage circuits. These sequentially closed circuits may be convenientlytermed message channels, and the period of time during which they areclosed, may be suitably termed total channel time.

It is possible, due to slight variations in characteristic operatingtime of the channel selecting relays for an overlapping of the totalchannel times to occur, which might cause an indication intended for onemessage channel to be indicated on two message channels. In eliminatingthis possibility, a circuit is provided which splits the total channeltime into three periods and permits the indication to be passed into itsown channel, only during the central period of the total channel time.

In a system, as shown in Figs. 1A, 1B and 10, this total channel time isdivided into three periods by the relays MR, S and S The message wire isconnected through the movable contact 28, of relay MR, so that a circuitmay be completed through positive or negative contact 28 to wires 23'!and 236 respectively, through negative or positive contacts 3|respectively, to wire 232, which is then carried to the message channelselecting relay to be connected to the various message channels.

By way of illustration, we will assume that the operating time of relaysMR, S and S are of equal length and equal to the operating time of achannel selecting relay such as relay I. Then relay S being in serieswith the relays L and L will operate during the same period of time asthe line relays, also the relay S will operate during the same period oftime as the particular message channel selecting relay which is thenbeing operated will operate. Also, We will assume that the system hasbeen initiated and the contacts 21 and 28 of relay MR have been moved toa positive. position by a positive potential being applied to the relayMR. This position of contacts 2'! and 28 energizes the relay S to apositive position as shown, but at this time the message circuit isbroken at contact 3|. With the contacts of relay S energized in apositive position the contact 29 of relay S is energized in a negativeposition as shown. It will be remembered that the channel selectingrelay operates at the same time as the relay S so that we may assume,that as soon as the contact 29 has reached a negative position, theperiod of time representing the total channel time has begun. Withcontact 29 in a negative position, the contacts of relay MR areenergized to a negative position, at which time the message circuit iscontinuous from the message wire 202 through negative contact 28, wire236, positive contact 3!, to wire 232, to any particular mes sagechannel. It is seen that a period of time has elapsed since thebeginning of the total channel time, and the instant that the contact 28arrived in a negative position. The movement of contacts 2'1, 28 to anegative position energizes the relay S to move the contacts 30 and 3!to a negative position. At the initiation of the movement of contact 3%,the message circuit heretofore traced is broken, but the total channeltime has not elapsed until the contact 29 of relay S has been initiatedin movement toward a positive position by the application of a positivepotential to the relay S Hence it is seen, that the message circuit isclosed only during the period of time that it takes the current to buildup sufficiently in the winding of relay S to initiate movement of itscontacts, thus making it possible to regulate the indication or messagetime by increasing the characteristic operating time of relay S t willof course be understood that to apply this same principle of sending themessage or indication during a time which is central in respect to thetotal channel time, to a way station where the stepping impulses are notrepeated by a line relay, as in Fig. 20, the stepping impulses shouldnot be repeated for the dispatchers message channel selecting bank ofrelays, and the contact 3i should be controlled by relay S instead ofrelay S The contacts of successive relays which close and open themessage channels, are normally in alternate positive and negativepositions, so that there is only one time that two successive contactsare in like positions. This may be illustrated by the relays l and 2.The message contacts 33 and 34 are in a positive position, the messagecontacts 3'! and 38 are in a negative position and the message contactsii and 42 are in a positive position etc. When the contact 34 moves to ane ative position, it is in a corresponding position with the contact3'! until the relay 2 is energized moving its contacts to a positiveposition, at which time the contact 31 is in a corresponding position tocontact 4!. Then relay 3 is energized to anegative position and contactM is in a position corresponding to contact it. Thus it is seen thatsince the message circuit is completed through contacts, assumingcorresponding polar positions of two successive relays, that the circuitis only completed from the time of operation of the first relay untilthe operation of the second relay of two adjacent relays in the series.This prin ciple has been carried out in the selection of all messagechannels.

In the instance of the dispatchers message channel selecting relays themessage wire is carried through contacts 28 and 3H assuming oppositepolar positions, through the wire 232 to contact Hit. With the relays lto H inclusive, in the at rest period, the third contacts of each clay lto is inclusive are connected in series. With the relays l to it in areverse position the fourth contacts of each relay are connected inseries. The message wire which is connected to contact lei, of relay llas heretofore explained, is mnuected to either third contact of relay itor the fourth contact of relay it according to r the position or" thecontacts of relay ill. Now,

it will be easily seen that a circuit is set up, as soc-n the relays i?have responded to the long positive impulse, through positive contactiiil of relay ii, through negative contact 95 of relay l6, positivecontact 96 of relay 15 in series to the contact 34 of relay i, so thatas soon as relay I recei es its negative impulse and moves to a reverseposition that a circuit is completed from the message wire through thecontacts as explained through wire 238 to the signal lever i9. As thelever SL is in a central position no indication is sent over the messagewire. Upon movement or" contact 31 of relay 2 to a positive position,the message channel for lever SL has been broken, and a message channelis set up through positive contact 31 of relay 2. As we have assumedthat the lever SML is assuming right hand position, we have a messagechannel set up through a circuit heretofore traced. Thus the messagechannels are successively made and broken by the movement of each relayin the order that it occurs until the relay ll is again moved to anegative position which transfers the message circuit through thefourth-contact of each relay l to it. The fourth contact of each relayin the channel selecting group being in series, the message channelswill be made and broken the same as shown heretofore for the thirdcontacts of the relays, until the system has completed the cycle.

'Although the selection of message channels has been more specificallyexplained for the message channel selecting relays at the dispatchersofiice, it is to be understood that the message channels at the waystation as shown in Fig. 1C are selected and controlled in the samemanner. Thus, all that'is necessary to have an indication sent from thedis'patchers ofiice to a given control relay such as relay SMR I is tohave the relay at the way station connected to its corresponding controlrelay through contacts of the last and next operated channel selectingrelay of both the dispatchers relay bank and the way station relay bank.

As the description of the message channel arrangement has progressedthus far, it is only necessary to state that as the system is normallyat rest, except when messages are to be transmitted, there is a channelat each way station and at the dispatchers oflice, which is made duringthis at rest'period of time. This message channel is connected tosomemeans at the way station, which in the case of Fig. 1C, is relay 1Nwhich will connect this message channel to the common wire Ztil, when anOS indication is to be transmitted from that way station. The messagechannel at the dispatchers omce which occursduring the at rest period,is connected to the relay IN in such a manner, that its ultimateconnection to the common wire at the way station will result in theenergization of relay IN. Thus means for initiation of the system fromthe way station is provided.

Modified form of way station In Fig. 2C, there is shown a modifiedorganization of connections for the message channel selecting relays,which will give more message channels per number of relays used, thanwill the connections as shown in Fig. 1C. It will also be noted that thestepping line impulses are not shown as being repeated by a line relay,which is an optional requirement and does not effect the synchronousoperation of the system on the assumption that the dispatchers channelselecting relays are controlled directly by the master relay MR. insteadof by the line relay L".

In Fig. 2C, a combination bank of relays, composed of relays A, B, C andD and relays etc., through the third contacts of each relay.

, tively.

X, Y and Z, is so arranged in a circuit, as to make it necessary thatthirty operations occur in this bank of relays, in a certainpre-determined sequence before this bank of relays has completed onecycle. This permits the closing of thirty message channels, which may beused for indication purposes. This combination bank of relays (Fig. 2C)is associated with an identical location on a railroad and withidentical control relays, as are shown for Fig. 1C, being indicated bycorresponding letters having suitable distinctive exponents.

The sequence of operation of this bank of relays is such, that the firstlong positive impulse picks up the relay 8T closing the front contact$69, which permits a portion of that long positive impulse to energizerelay Z to a positive position, after which, the circuit arrangementpermits the positive and negative impulses of the normal stepping rateto successively energize the relays A, B, C and D to their reversedotted positions. Upon the movement of relay D to its positive position,the circuit arrangement is such that, the next succeeding impulse, whichis negative, energizes the relay X to a negative position after whichthe relays A, B, C and D are successively operated to their normalposition. Thus in like manner, at the completion of the successiveoperation of the relays A, B, C and D to either their reverse positions,or their normal positions, a relay in the group X, Y and Z, succeedingthe last operated relay in that group, is operated to its oppositeposition, until the relays X, Y and Z have each been operated to theirreverse positions and back to their normal positions, except the relayZ, which remains in its at rest position. The relay ST acts as ablocking relay to hinder the relay Z from responding to its impulse ofnormal order, and

. requires a long positive impulse to pick it up,

closing a contact so that relay Z may respond.

The operating contacts of the ABCD group of relays are the same as thegroup in the dispatchers office, so that, when negative and pos- 1 itiveimpulses are alternately placed on the wire 262, the relays A, B, C andD are operated to reverse positions and when positive and negativeimpulses are placed on the wire 264 the relays A, B, C and D areoperated to normal positions. In each case, after the relays A, B, C andD have either completely reversed, or completely returned to normal,circuits are completed to the wires 263 and 254 respectively, which arethen connected to the wires 262 and 264 respec- It is deemed, that thisexplanation will make it necessary to trace only the circuits in thegroup of relays X, Y and Z to the wires 262 and 254, stating that the A,B, C and D relays have operated, and again picking up the circuit atwires 263 and 255 respectively.

With the equipment at rest, the long positive impulse is impressed onthe stepping wire through wire 242, the negative contact I52 of relay Z,wire 245, positive contact I4I, wire 253, negative contact I48, to thewire 284, through the contacts of relays A, B, C and D, wire 265,negative contact I44, wire 256, through the relay 8T to the common wire204, thus picking up the relay 8T The front contact I69 is thus closed,completing a circuit through wire 259, and through the relay Z to thecommon wire 20$, energizing relay Z to a positive position.

With the relay Z in a positive position, the next four succeedingimpulses flow from the stepping wire till, through wire 242, positivecontact 152, wire negative contact I46, wire 249, positive contact 644,wire 262, to reverse the contacts of relays A, B, C and D by theirrespective impulses. Relays A, B, C and D being reversed, the circuitcontinues through the wire 263, positive contact 554, wire 244, positivecontact I42, through relay X to the common wire 200, energizing thecontacts of relay X with a negative impulse to a negative position.

With the relay X in a negative position, a circuit is completed from thestepping wire 2%, through wire 242, positive contact I52, wire 251,negative contact I46, negative contact I40, wire 243, negative contactI47, to the wire 264, thus returning the contacts of relays A, B, C andD to normal by their respective impulses. The circuit then continuesthrough the Wire 265, negative contact I 44, wire 24?, negative contactI50 of relay Y, to the common wire 2%, thus operating the contacts ofrelay Y with a positive impulse to a positive position.

With the relay Y in a positive position, a circui't is completed fromthe stepping wire 20!, through wire 242, positive contact I52, wire2527, positive contact 146, wire 258, positive contact N53, to the wire262, to reverse the contacts of relays A, B, C and D by their respectiveimpulses. The circuit then continues through wire 263, positive contactI54, wire 244, negative contact M2, wire 254, positive contact I55,through relay Z to the common wire 209, thus operating the contacts ofrelay Z with a negative impulse to a negative position.

With the relay Z in a negative position, a circuit is completed from thestepping wire 26!, through wire 242, negative contact I52, wire 245,negative contact MI, wire 264, thus returning the contacts of relays A,B, C and D to normal by their respective impulses. The circuit is thencontinued through the wire 265, negative contact I44, wire 241, positivecontact I50, wire 248, negative contact Hi3, wire 262, through relay Xto common wire 2%, thus operating the contacts of relay X with apositive impulse to a positive position.

With relay X in a positive position, a circuit is completed from thestepping wire 20 I, through wire 242, negative contact I52, wire 245,positive contact MI, wire 253, positive contact I48, to wire 262, toreverse the contacts of relaysA, B, C and D by their respectiveimpulses. The circuit then continues through wire 263, negative contactI54, wire 25!, positive contact I49, wire 250, through relay Y to commonwire 200, thus operating the contacts of relay Y with a negative impulseto a negative position.

Thus one cycle comprising thirty operations of the relays in thiscombination bank has been completed. Of these thirty operations therelays X, Y and Z have made six while the relays A, B, C and D havecompleted six times four namely twenty-four operations.

For the purpose of showing the thirty message channels obtainable withthe combination of connections for the message channel selecting relays,as illustrated in Fig. 26, reference will be made to Fig. 3, in whichthe positions of the relays are represented by positive and negativesigns arranged with three in the left column and four in the right asare the relays X, Y, Z and A, B, C, D, respectively, in Fig. 2C. Inother words, a positive sign represents a contact in the right hand orpositive position, and a negative sign represents a contact in the lefthand or negative position, as heretofore explained. These symbolicrepresentations of the positions of contacts, are so arranged that theirposition in respect to each other represent contacts on relays as shownin Fig. 2C, which have correspond- 5 ing positions in the drawings, forinstance as followsz-positive sign 266 represents contact I45 in apositive position, negative sign 26! represents contact I5! in anegative position, positive sign 268 represents contact I56 in apositive position, positive sign 269 represents contact I59 in apositive position, negative sign 210 represents contact I62 in anegative position, positive sign 2' represents contact I65 in a positiveposition, and a negative sign 212 represents contact I68 in a negativeposition. Thus, the positive and negative signs as included undercombination I (see Fig. 3) represent a set of contacts. on the relays A,B, C and D, and X, Y and Z, which will give one message channel whenassuming this given combination of positions. In other words,

the contacts on said relays, which operate se-- quentially as heretoforedescribed, are represented diagrammatically under the combinations I 2 34 etc. up to 30 such that each successive movement of relay contacts isrepresented in the diagram by successive combinations.

By way of illustration, the specific representation as shown bycombination 8 of Fig. 3 is completely shown in diagrammatical form inFig. 3A. In this drawing Fig. 3A, the relays and the contacts are givenreference symbols to correspond with the drawing Fig. 20, havingsuitable exponents to distinguish them. However, in each case, the factsrepresented are identical, and may be enumerated, as fo-llows:--

(1) The 8 diagram means, that this combination is set up by the eighthmovement of relay contacts in response to their respective impulsesafter the system has been initiated;

(2) The positive and negative signs represent the positions of thecontacts after the relays have thus assumed the eighth combination ofpositions;

(3) The dotted line through the positive and negative signs representsthe particular contacts which must be connected in series to constitutethe message channel chosen for that particular combination. Each of thethree enumerated facts is clearly set forth diagrammatically in Fig. 3A.

The symbolic showing in Fig. 3 serves peculiarly adaptable fordescribing and setting forth the thirty individual message channels thatmay be obtained by seven relays. As has been heretofore explained inconnection with Fig. 1A and 1C, when a circuit is closed through twosuccessive contacts in series, which are .assuming like positions, acircuit is closed but once during a complete cycle. This is also true ofthe message channels for the Way station shown in Fig. 2C,

if this rule of determining message channels is applied to both columnsof relays used in Fig. 2C, it will be noted from Fig. 3 that in nearlyevery case the channel circuit (represented by a dotted line) includessuccessive like polarity signs in both columns, the reason why this isnot necessary for all cases will presently be explained.

As there is but one movement of relay contacts in the XYZ group ofrelays as compared to the four movements of the ABCD group of relays,

then we may term these positions assumed by the XYZ group, the groupcharacteristic, and the positions assumed by the ABCD group the individual characteristic. Referring to Fig. 3, the groups of combinationshave been designated by the letters XYZ having suitable exponents. It

is noted that the group characteristics or groups XYZ XYZ XYZ XYZ XYZand XYZ are alternately two positive contacts and two negative contactsrespectively which contacts are selected on successively operatedrelays, thus giving six distinctive group characteristics.

It is necessary in the dispatcher's message channel group of relays I toI 'I (see Fig. 1A) to have an odd number of relays, in order that thegroup could complete a cycle of operation. To meet a similarrequirement, for the message channel selecting relays A, B, C and D, onerelay from the group XYZ has been operated to complete the number ofoperations in each half cycle to an odd number.

In choosing the individual characteristic, two contacts which operate insuccession are selected to be connected in series. However, it will benoted, that with the group characteristic contacts (relays X, Y and Z ofFig. 3) connected in series with the individual characteristic contacts(relays A, B, C and D), that a combination is obtainable so that thecombination of the group characteristic is such, that its sign completesthe number of signs for the individual characteristic to 5, thus makingpossible five combinations for each group characteristic. For thisreason only contacts of three relays are required for certain messagechannels as clearly shown by the conventional showing in Fig. 3.

Let us consider more specifically the combination I5 which has a groupcharacteristic of two positive contacts. A circuit is carried throughthese two positive group characteristic contacts (relays X, Y and Z) andthrough the last positive contact (contact of relay D) in the individualcharacteristic. This positive individual characteristic contact does notchange when combination I5 is completed, however, thegroupcharacteristic has changed to negative, thus breaking thetemporarily closed message channel. Thus by using distinctive groupcharacteristics, in combination with four distinctive individualcharacteristics, five distinctive combinations are obtainable for eachgroup characteristic.

Although there are but thirty combinations obtainable with '7 relays,grouped as illustrated, it is to be understood that the total number ofrelays may be decreased or increased and operated on the same underlyingprinciple, and that the number of combinations will be correspondinglychanged, rendering the grouping adaptable for specific requirements.

It will be noted that the message channel shown in combination M3 is themessage channel which is normally completed while the system is at rest,hence this message channel may be used for initiation purposes. Such amessage channel is needed at each and every way station.

In embodying these principles for selecting message channels, in thepresent invention as shown in Fig. 20 the combination 30 (Fig. 3) isused for initiation purposes, and the combinations 2 3 G and 5 (Fig. 3)are used for message channels over which to control the relays SR SMRand DB and to give an OS indication from the track relay TRrespectively.

The relay IN is so constructed that it has a slow releasing period,which is greater than the length of time that is required for the systemto complete one cycle. Thus, as the relay TlR. changes its position thecontact 2 I3 momentarily closes a circuit which energizes the relay INas is obvious from the drawings. As the release period of the relay INis greater than the length of time required for the operation of onecycle of the system, then it is always assured that the sys- 1 tem willcomplete at least one cycle after the relay TB has changed positions,thus the OS indication is insured of being indicated to the dispatcher,this on the assumption that the OS condition will persist for at leastone time cycle.

With the system at rest, the message wire 252 is connected to commonthrough a message channel as obtained in combination 35 when the contacti'lal is picked up due to momentary energization of relay 1N Thisinitiation message circuit for the dispatchers ofiice has beenheretofore described, so that the initiation circuit at the way stationas shown in Fig. 2C need only be traced from the message Wire asfollows:from message wire 282, through wire 255, negative contact 555,wire'252, negative contact I5I, wire 2T4, negative contac 533', wire 255, front contact I'll}, to the common wire 2%, thus initiating thesystem. The OS indication, or indication of change of the position ofthe track relay TR is now ready to be transmitted over the combinationas set up in Fig. 3, namely combination 5 After the message channelselecting relays have been stepped along in synchronism, with themessage channel selecting relays at the dispatchers oiiice, until thisfifth channel is set up, then the following circuit is completed for theOS indication:negative battery from battery 2'55, back contact I31, wire21?, positive contact I68, wire 278, positive contact I45, wire 245,positive contact 956, wire 255, through the message wire 292 to thedispatchers office, through positive contact 28, wire 231, negativecontact Si, wire 232, positive contact llli, negative contact 5,positive contact 95, negative contact 85, positive contact 8i, negativecontact Tl, positive contact negative contact 59, positive contact 65,negative contact 5!, positive contact 5'7, negative contact 53, positivecontact 45, positive contact 45, through the OS relay to the common wire205. Thus contact E is energized to a negative position illuminating theindicating lamp I.

Let us again assume the system to be at rest, and that the dispatcherwishes to reverse the switch TSW so that the east bound trafiic may berouted into the passing siding of PS To accomplish this result thedispatcher moves the lever SML to a left hand position, which initiatesthe system and steps the message channel selecting relays in the waystation as shown in Fig. 2C, in synchronism with the message channelselecting relays in the dispatchers ofiice, in a manner heretoforedescribed, until the third message channel is set up, at which time acontrol impulse is sent to the relay SMR This control impulse flowsthrough a circuit in the dispatchers ofilce as heretofore described, tothe way station over the wire 262, to the relay SlVlR through a oil nittraced as follows:-from the message Wire 252, through the wire 255,positive contact [55 of relay Z, wire 24-6, positive contact I45, ofrelay X, wire 2H3, negative contact I58 of relay D, positive contactI65, positive contact 552, wire 28 3, through the relay SMR to thecommon wire Elli]. Thus the polar contact of the relay SMR is energizedto a negative position, which in turn controls switch machine SM thusmoving the switch TSW to a reverse position. The system continuesstepping until two cycles of the message channel selecting groups ofrelays has been completed in a manner as heretofore described.

Now let us consider that the dispatcher wishes to clear the signal SE Toaccomplish this, the

dispatcher moves the lever SL to a right hand position, which initiatesthe system and steps the message channel relays in the dispatchersofiice along in synchronism with the message channel relays at the Waystation as shown in Fig. 20, in a manner as heretofore described. Whenthe message channel selecting relays have been stepped along until thesecond message channel is set up, a positive impulse is sent over themes sage wire 202 from the dispatchers oifice the way station shown inFig. 20 in a manner hereto fore described and which passes through acircuit in the way station as shown in Fig. 20, being traced asfollows:from the message wire 202, through wire 255, positive contactI56 of relay Z, wire 246, positive contact I45 of relay X, wire 278,negative contact I68, relay D, positive contact I65 of relay C, negativecontact I62, of relay B, negative contact I59 of relay A, wire 285,through the relay SR to the common wire 2%. Thus the signal relay SR isenergized with positive potential. When the message channel relays havebeen stepped along until the fourth message channel has been set up, acircuit is completed in the dispatchers office which places a positiveimpulse upon the stepping wire 252 as heretofore explained which in turnis placed upon the relay DB at the way station shown in Fig. 20 througha circuit traced as follows:-from the message wire 202, through wire255, positive contact I56 of relay Z, wire 246, positive contact I45 ofrelay X, wire 278, negative contact I68 of relay D, negative contact I65of relay C, wire 283, through the relay DR to the common wire 25!]. Thusthe relay DH is energized with positive potential, which causes itspolar contact to move to a positive position. With the polar contacts ofrelays SR and DR in a positive position the signal SE is cleared,allowing east bound traific to proceed over the reversed switch TSW ontothe passing siding PS The message channel selecting relays step alonguntil they have completed twocycles.

Having thus shown, and described, several specific embodiments of arather involved and comprehensive system, for carrying out certainfunctions, it is desired to be understood that the particulararrangement of devices and circuits illustrated need not be adhered to,but that many changes, modifications and additions may be made, in theindividual devices as well as their co-ordination with each other,without departing from the scope or spirit of the invention as demandedby the scope of the appended claims.

What we claim is:

1. In a train dispatching system of the wayside signal control type, thecombination with a large number of wayside signals located along therailway track and each controlled by traffic conditions ahead, of meansfor controlling said signals distinctively over the same line wirescomprising, a bank of relays in the dispatchers ofl'ice, a bank ofrelays at each of'a plurality of way stations, means for operating therelays of each bank sequentially in a particular order, and over anuninterrupted line circuit, in such a way that corresponding relays ofall the banks are operated synchronously and sothat corresponding relaysof all banks at all times assume corresponding positions, and aplurality of message circuits for controlling said signals closedsequentially and each including the same line wire and includingcontacts of corresponding relays of the dispatchers oiiice bank and aparticular way station bank.

2. In a train dispatching system of the wayside signal control type, thecombination with a large number of wayside signals each controlled bytrafiic conditions ahead located along the railway track, of means forcontrolling said signals distinctively over the same line wirescomprising, a bank of relays in the dispatchers ofiice, a bank of relaysat a particular way station, means for operating the relays of each banksequentially in a particular order in such a way that corre spondingrelays of both banks are operated synchronously and so thatcorresponding relays cf the two banks at all times assume correspondingpositions, and a plurality of message circuits for controlling saidsignals subject to traliic conditions ahead closed sequentially and eachinclud ing the same line wire and including contacts of correspondingrelays of the dispatchers oflice bank and a particular way station bank.

3. In a train dispatching system of the wayside signal control type, thecombination with a large number of wayside signals located along therailway track, of means for controlling said signals distinctively overthe same line wires comprising, a bank of stepping and channel selectingrelays in the dispatchers office, a bank of channel selecting relays ata particular way station, normally inactive stepping means for operatingthe relays of each bank sequentially in a particular order in such a waythat corresponding relays of both banks are operated synchronously andso that corresponding relays of the two banks at all times assumecorresponding positions, means for rendering said stepping means activeto operate said channel selecting relays through a specific pluralnumber of cycles of operation, and a plurality of message circuits forcontrolling said signals closed sequentially and each including the sameline wire and including contacts of corresponding relays of thedispatchers ofifice bank and said way station bank.

4. In a train dispatching system of the wayside signal control type, thecombination with a large number of wayside signals located along therailway track, of means for controlling said signals distinctively overthe same line wires comprising, a bank of channel selecting relays inthe dispatchers ofiice, a bank of channel selecting relays at each of aplurality of way stations, nor-' mally inactive stepping means includingan uninterrupted wire running from the oflice to each Way-station foroperating the relays of each bank sequentially in a particular order insuch a way that corresponding relays of all banks are operatedsynchronously and so that corresponding relays of all banks at all timesassume corresponding positions, means controllable from any way stationand from said dispatchers office for rendering said stepping meansactive to operate said channel selecting relays through a specificnumber of cycles of operation, and a plurality of message circuits forcontrolling said signals closed sequentially and each including the sameline wire and including contacts of corresponding relays of thedispatchers ofiice bank and a particular way station bank.

5. In a train dispatching system of the wayside signal control type, thecombination with a large number of wayside signals located along therailway track, of means for controlling said signals distinctively overbut two line wires and a common wire comprising, a bank of channelselecting relays in the dispatchers ofiice, a bank of channel selectingrelays at each of a plurality of way stations, normally inactivestepping means for operating the relays of each bank sequentially in aparticular order in such a way that corresponding relays of all banksare operated synchronously and so that corresponding relays of all banksat all times assume corresponding positions, means for rendering saidstepping means active to operate said channel selecting relays through aspecific plural number of cycles of operation, a plurality of messagecircuits for transmitting OS indications and controlling signals eachincluding the same line wire and including contacts of correspondingrelays of the dispatchers ofiice bank and a particular way station bank.

6. In a train, dispatching system of the wayside signalcontrol type, thecombination with a large number of wayside signals located along therailway track, of means for controlling said signals distinctively overonly two line wires and a common wire comprising, a bank of channelselecting relays in the dispatchers oflice, a bank of channel selectingrelays at each of a plurality of way stations, normally inactivestepping means for operating the relays at each bank sequentially in aparticular order in such a way that corresponding relays of all banksare operated synchronously and so that corresponding relays of all banksat all times assume corresponding positions, means controllable from anyway station and from said dispatchers ofiice for rendering said steppingmeans active to operate said channel selecting relays through a specificplural number of cycles of operation, a plurality of message circuitsfor transmitting OS indications and controlling signals each includingthe same line wire and including contacts of corresponding relays of thedispatchers ofiice bank and a particular way station bank.

7. The method of controlling any one of a plurality of distant waysidesignals of a railway distinctively over the same line wire, whichconsists in a chain of relays at a dispatchers ofiice and another chainof relays at a distant way station, in causing the relays of the twochains to be operated sequentially in synchronism so that correspondingrelays of the two chains assume corresponding positions at all times andin operating said relays through complete cycles when operating, and incontrolling said signals subject to trafiic conditions in advancethereof distinctively and separately over the same line wire andcorresponding contacts of corresponding relays of the two relay chains.

8. In a train dispatching system of the wayside signal control type, thecombination with a large number of wayside signals located along therailway track, of means for controlling said signals distinctively overthe same line wires comprising, a bank of relays at a dispatchersoffice, a bank of relays at a distant way station, stepping means foroperating the relays of both banks sequentially in a particular order insynchronism and in such a way that corresponding relays of both relaybanks assume corresponding positions at. 'all times and operate untilthe cycle of operation is completed at which point said stepping meansis locked up, a slow-acting relay for unlocking 'said stepping means anda plurality of message circuits for controlling said signals closedsequentially and each including the same line wire and includingcontacts of corresponding relays of the dispatchers ofiice bank and theway station bank.

9. In a train dispatching system of the wayside signal control type, thecombination with a large number of wayside signals located along therailway track, of means for controlling said signals distinctively overthe same line wires comprising, a bank of relays at a dispatchersofiice, a bank of relays at a distant way station, stepping means foroperating the relays of both banks sequentially in a particular order insynchronism and in such a way that corresponding relays of both relaybanks assume corresponding positions at all times and operate until thecycle of operation is completed at which point said stepping means islocked up, synchronizing means for normally and automatically bringingsaidrelays in step and restarting said stepping means once after eachinitiation of the system, whereby,said system opcrates through at leasttwo cycles of operation for each initiation, and a plurality of messagecircuits for controlling said signals closed sequentially and eachincluding the same wire and including contacts of corresponding relaysof the dispatchers ofiice bank and the way station bank.

10. In a train dispatching system of the wayside signal control type,the combination with a large number of wayside signals located along therailway track, of means for controlling said signals distinctively overthe same line wires comprising, a bank of relays at a dispatchersoflice, a bank of relays at a distant way station, stepping means foroperating the relays of both banks sequentially in a particular order insynchronism and in such a way that corresponding relays of both banksassume corresponding positions at all times and operate until the cycleof operation is completed at which point said stepping means is lockedup, synchronizing means including a slow acting relay for bringing saidrelays in step and restarting said stepping means, a plurality ofmessage circuits for controlling said signals closed sequentially andeach including the same line wire and including contacts ofcorresponding relays of the dispatchers ofiice bank and the way stationbank, and means for energizing said slow-acting relay and initiatingoperation of said stepping means.

11. In a train dispatching system of the wayside signal control type,the combination with a large number of wayside signals located along therailway track, of means for controlling said signals distinctly over thesame line wires comprising, a bank of relays at a dispatchers office, abank of relays at a distant way station, stepping means for operatingthe relays of both banks sequentially in a particular order insynchronism and in such a way that certain relays of both relay banksassume certain positions at certain non-recurring times and the relaysof the banks operate until the cycle of operation is completed at whichpoint said stepping means is locked up, a slow-acting relay forunlocking said stepping means, and a plurality of message circuits forcontrolling said signals closed sequentially and each including the sameline wire and including contacts of corresponding relays of thedispatchers office bank and the way station bank another slow-actingrelay which so long as it assumes its de-energized condition whilehaving its winding energized applies current to said first mentionedslow-acting relay, and a contact on another slow-acting relay forcontrolling the re-energization of said first mentioned slow-actingrelay at the end of the subsequent cycle of operation of said relaybanks.

12. In a centralized traffic controlling system for railroads; a distanttrack switch; a switch machine for operating said track switch; andmeans for controlling said switch machine from a central officecomprising; a series of relays in said central office, a correspondingseries of relays at said distant track switch, one line relay onlyassociated with each of said series of *elays, a line circuit extendingbetween said central office and said distant track switch for connectingsaid line relays in a series circuit uninterruptible except at saidcentral oifice, means for controlling the energization of said linecircuit only from said central ofiice, circuits for interconnecting eachof said series of relays with its respective one line relay to cause therelays of each series to be sequentially energized upon successiveenergize,- tions of its one line relay, thereby causing correspondingrelays of the two series of relays to be energized simultaneously whensaid line circuit is energized, and a message circuit for controllingsaid switch machine available when a particular pair of saidcorresponding relays of said two series of relays is energized.

13. In a centralized trafiic controlling system for railroads; a distanttrack switch; switch machine for operating said track switch; and meansfor controlling said switch machine from a central office comprising; aseries of relays in said central oifice, a corresponding series ofrelays at said distant track switch, one line relay only associated witheach of said series of relays, a line circuit extending between saidcentral office and said distant track switch for connecting said linerelays in a series circuit uninterruptible except at said centralofiice, means for controlling the energization of said line circuit onlyfrom said central ofiice, circuits for interconnecting each of saidseries of relays with its respective one line relay to cause the relaysof each series to be sequentially energized upon. successiveenergizations of its one line relay, thereby causing correspondingrelays of the two series of relays to be energized simultaneously, aslow acting relay associated with each of said series of relays whichprevents the initiation of operation of said series unless said slowacting relay is first operated, means for controlling said slow actingrelay, and a message circuit including but one additional line wire forcontrolling said switch machine rendered available for controlling saidswitch machine when a particular pair of corresponding relays of saidtwo series of relays is energized.

14. In a centralized trafiic controlling system for railroads; a distanttrack switch; a switch machine for operating said track switch; andmeans for controlling said switch machine from a central oilicecomprising; a series of polar relays of the two position type at thecentral ofiice, a corresponding series of polar relays of the twoposition type at said distant track switch, means for successivelyoperating the corresponding pairs of relays of said two series of relaysfrom their normal to their reverse position during the first half cycleof operation and operating successively corresponding pairs of relaysback to their normal position during the second half of the cycle ofoperation, the relays of each pair being operated simultaneously, and adistinct message circuit connecting said central office and said trackswitch completed upon each operation of a pair of relays, whereby thereare rendered available two message circuits for each relay of a seriesduring each cycle of operation of said system.

15. In a centralized traflic controlling system for railroads; a distanttrack switch; a switch machine for operating said track switch; andmeans for controlling said switch machine from a central oflicecomprising; a series of polar relays of the two position type at thecentral oifice, a corresponding series of polar relays of the twoposition type at said distant track switch, means for successivelyoperating the corresponding pairs of relays of said two series of relaysfrom their normal to their reverse position during the first half cycleof operation and operating successively corresponding pairs of relaysback to their normal position during the second half of the cycle ofoperation, the relays of each pair being operated simultaneously, and aplurality of message circuits in number equal to twice the number ofrelays in each series, each message circuit of which includes thecontacts of two adjacent relays, closed sequentially during operation ofsaid relays, and means for controlling said switch machine over one ofsaid message circuits.

16. An impulse counting group of relays comprising, a series of twoposition polar counting relays of the first order, a series of twoposition polar counting relays of the second order, and interconnectingcircuits to efiect repeat operation through the series of relays of thefirst order for each operation of one of said relays of the secondorder, whereby the total number of impulses which may be absorbed bysaid counting group of relays is equal to twice the product of thecounting relays of the first order and the number of counting relaysplus one of the second order.

17. For use in a centralized trafiic controlling system for railways, abank of polar relays of the two-position stick type, means forsuccessively operating the relays each to its opposite position, andthen each back to its first position by energizing a circuit with energyof alternating polarities.

18. For use in centralized traffic controlling systems for railways, incombination, a chain of two-position polar stick type relays, anenergizing circuit for the first relay of the chain including its ownpoint of one polarity, each succeeding relay having an energizingcircuit including its own point of one polarity, the point of the nextpreceding relay of the same polarity, and points of alternatepolarities, respectively, of the remaining preceding relays.

19. For use in centralized traific controlling systems for railways, incombination, a chain of two-position polar stick type relays, anenergizing circuit for the first relay of the chain including its ownpoint of one polarity, each succeeding relay having an energizingcircuit including its own point of one polarity, the point of the nextpreceding relay of the same polarity, and points of alternatepolarities, respectively, of the remaining preceding relays, a secondenergizing circuit for each relay relatively arranged as above, but thecase of each relay, relating to the point of such relay of oppositepolarity to that recited above.

20. In a control means of the selector type; a bank of selecting relays;means for subjecting said bank of relays to a series of spaced currentimpulses; and an energizing circuit for each relay, the energizingcircuit for each relay being completed only upon the operation of apreceding relay but being efiective to cause the operation of its relayonly upon the reception of the next impulse of said series of impulsesfollowing that impulse which caused the operation of the precedingrelay, and the operation of each relay making its energizing circuitimmune to subsequent current impulses, whereby each relay responds onlyto its respective impulse in said series of impulses.

2.1. In a control means of the selector type; a bank of selectingrelays; means for subjecting said bank of relays to a series of spacedcurrent impulses; an energizing circuit for each relay of the bank, theenergizing circuit for each relay being completed only upon theoperation of a preceding relay but being effective to cause theoperation of its relay only upon the reception of the next impulse ofsaid series of impulses following that impulse which caused theoperation of the preceding relay, and the operation of each relay makingits energizing circuit immune to subsequent current impulses, wherebyeach current impulse causes operation of but one of the relays of thebank of relays, and whereby the relays are operated in succession; andchannel circuits sequentially closed by said bank of relays.

22. In a control means of the selector type, in combination, a bank ofselecting relays, an energizing circuit for each relay, means forsubjecting the bank to a series of spaced current impulses, theenergizing circuit for each relay being completed only after theimmediately preceding relay has been operated, and the operation of eachrelay making its energizing circuit immune to subsequent currentimpulses, whereby each current impulse causes operation of but one ofthe relays of the bank of relays, and the relays are operated insuccession, another energizing circuit for each relay of the bank, eachrelay being a twoposition relay, said another circuits being related toeach other as are the first said energizing circuits, but related, ineach case, to the other position of the relay than the position to whichthe first said energizing circuits are related.

23. In combination, a first line wire connecting an office and astation, a movable device at said station, means operating in responseto a change in the position of said device to deliver a starting impulseto said first line wire, a second line wire connecting said ofiice andstation, a bank of stepping relays in said ofilce responsive to saidstarting impulse for delivering another impulse to said second linewire, means at the station responsive to said other impulse to deliverto said first line wire an indication impulse under the control of saiddevice, and means at the ofiice selectively controlled by saidindication impulse.

24. In a centralized trafiic control system for railroads, a controloi'fice, a plurality of way stations, a stepping circuit, automaticimpulsing means for placing impulses on said stepping cir cuit,step-by-step means at each of said stations and said control office alloperated in synchronism by the application of said impulses to saidstepping circuit, trafiic controlling devices at each way station, and astarting circuit extending between said control ofiice and said waystations capable of being closed at each station when a change in theposition or condition of one or more of said traffic controlling devicesoccurs at a station if said automatic impulsing means is not inoperation.

FOREST B. I-IITCI-ICOCK. OSCAR H. DICKE.

